import java.io.*;
import java.util.StringTokenizer;

/**
 * 求给定的一群数里的最大异或对
 */
public class Main {
    static int M = 3000100;
    static int[][] son = new int[M][2];
    static int idx = 0;
    public static void insert(int x){
        int p = 0;
        for (int i = 30; i >= 0; i--) {
            int u = x >> i & 1;
            if (son[p][u] == 0){
                son[p][u] = ++idx;
            }
            p = son[p][u];
        }
    }
    public static int query(int x){
        int p = 0;
        int res = 0;
        for (int i = 30; i >= 0; i--) {
            int u = x >> i & 1;
            if (son[p][1-u] != 0){
                p = son[p][1-u];
                res = res * 2 + 1-u;
            }else{
                p = son[p][u];
                res = res * 2 + u;
            }
        }
        return res ^ x;
    }

    private static class InputReader {
        private static final int BUF_SZ = 65535;
        private BufferedReader in;
        private StringTokenizer st;

        public InputReader(InputStream in) {
            this.in = new BufferedReader(new InputStreamReader(System.in), BUF_SZ);
            st = new StringTokenizer("");
        }

        public String next() throws IOException {
            while(!st.hasMoreTokens()) {
                try {
                    st = new StringTokenizer(in.readLine());
                }catch (IOException e) {
                    throw new IOException(e);
                }
            }
            return st.nextToken();
        }

        public int nextInt() throws IOException {
            return Integer.parseInt(next());
        }
    }
    private static InputReader in = new InputReader(System.in);
    private static PrintWriter out = new PrintWriter(new OutputStreamWriter(System.out));

    public static void main(String[] args) throws IOException {
        int n = in.nextInt();
        int[] a = new int[n];
        for(int i = 0; i < n; i++) {
           int x = in.nextInt();
           a[i] = x;
           insert(x);
        }
        int max = 0;
        for (int i = 0; i < n; i++) {
            max = Math.max(max,query(a[i]));
        }
        System.out.println(max);
        out.flush();
    }
}